<nz-input-group [nzAddOnBefore]="'用户名'">
  <input type="text" nz-input  [(ngModel)]="f.cell"/>
</nz-input-group>

<nz-input-group [nzAddOnBefore]="'密码'">
  <input type="text" nz-input [(ngModel)]="f.code" />
</nz-input-group>
